1. Field of the Invention
The present invention relates to a storage system used for a computer system. Particularly, the invention relates to a method of managing the configuration of a volume and failure and a system for management in a storage area network (hereinafter called SAN) in which a real volume provided from a storage system is provided to a server as a virtual volume via a volume virtualizing function of a virtualization system.
2. Description of the Prior Art
(1) Regarding SAN
SAN is a dedicated network to input/output to/from a storage system. By introducing the SAN, we can realize highly scalable and available storage systems which provides high speed data transfer, and we can use the storage resources effectively, so in recent years the SAN is widely spreading.
(2) SAN Manager
To operate different types of storage systems consolidated into a SAN without a disruption, an administrator acquainted with the operation of each type is required, and the management cost is high. In SAN management, it is particularly important to monitor the availability which is the base of daily operation of each unit (a server, a switch and a storage system) connected to the SAN. Software for monitoring availability is hereinafter called a SAN manager. The SAN manager has two major functions of a configuration management function and a failure monitoring function. The configuration management function is a function for periodically discovering units composing the SAN and acquiring information from a management agent existing in each unit composing the SAN, detecting physical topology in the SAN from the acquired information, always visualizing the latest topology and providing it to a SAN manager user, in other words, a SAN administrator. The failure monitoring function is a function for receiving event notification such as hardware failure and the lowering of the performance issued by each unit and the occurrence of an event such as failure and the lowering of performance based upon unit information periodically acquired from a management agent existing in each unit and notifying the user of the event. The user can manage the availability of a unit from a single console using the SAN manager by these two functions and reduce costs for operation such as the reduction of SAN administrators.
(3) Virtualization System
The storage virtualization technology is one of the storage management techniques in the SAN. The storage virtualization technology is disclosed in U.K. Patent Application No. 2351375. The U.K. Patent Application No. 2351375 discloses that a device called a storage server is provided with the following two functions. 1) A function that discovers and manages multiple volumes which storage systems connected to the storage server provides and generates a storage pool. 2) A function that generates a virtual volume based upon one or more real volumes in the storage pool, and responds I/O access from the server to the virtual volume. A server or a switch provided with these two functions is hereinafter called a virtualization system. A user of the server has only to request a virtualization system to allocate a virtual volume by installing the virtualization system in a SAN and is not required to be conscious of the physical arrangement of storage systems connected to the virtualization system. As a result, a SAN administrator can unifically allocate volumes to servers.